I am installing on a Centos 5 system which uses the yum tool. I also
have the http://rpmforge.net/repository enabled. I need that for
librsync and librsync-devel which provides rsync capabilities when the
remote file details are not available (like in FTP).
All of these requirements are found on the duplicity main
page.

Do this as the user that you’ll be running the backup as – it makes
things easier. If you have your own existing keys and know how to import
them, you can skip this step. Otherwise, we’ll create a key just for
encrypting the backups before sending them to our backup server (in case
of rogue system admins at Amazon).

At this point, let me interrupt and talk about the Passphrase. You can
make this anything, but I would recommend avoiding special characters
(especially dealing with <> ‘ ” ` ) that might be interpreted by
your system shell. I generated a 15 character password online using
only numbers, letters, and LETTERS. You will need to keep track of the
password – you will need it later when you write the backup script.

We need to generate a lot of random bytes. It is a good idea to perform
some other action (type on the keyboard, move the mouse, utilize the
disks) during the prime generation; this gives the random number
generator a better chance to gain enough entropy.
+++++++++++++++++++++++++.+++++++++++++++++++++++++++++++++++..+++++.++
+++++++++++++..++++++++++.+++++++++++++++..++++++++++++++++++++++++++++
++.>+++++..............................................................
.......................................................................
......+++++
gpg: /home/ytjohn/.gnupg/trustdb.gpg: trustdb created
public and secret key created and signed.key marked as ultimately
trusted.pub 1024D/53F0891A 2008-04-08
Backup Key (Backup key for duplicity) <[email protected]>
Key fingerprint = 135A 1533 5C94 3A58 5398 7467 98A0 C424 5BF0 8C2E
sub 2048g/630FAA4F 2008-04-08

We see our key ID is 53F0891A – make a note of this for the backup
script.

Essentially, what we want is a script that you just run and it will
perform the backup for you. For my purposes, I want to backup to
Amazon’s Simple Storage Service (s3). To do this, you will need to
sign up for the service (no cost to signup, just pay for space/bandwidth
used) and get the AWS/AWS secret keys (think of them like
username/passwords).
The following script will backup a directory called /mnt/backups to an
Amazon bucket called j123backup (the bucket name must be unique between
all Amazon S3 users). Please note that while you can use the same script
and gpg keys on multiple servers (or have multiple backup scripts on the
same server backing up different directories), you will want to make a
separate bucket for each different source backup.

As a final note, you can definitely point your backup at another
destination such as ftp or scp. I later ended up choosing an scp server
over Amazon S3.–
Backing up with duplicity and Amazon S3 By YourTech John on October 26,
2009 7:00 AM